Mosquito Heaven

Chemical ecologist Zain Syed of the Walter Leal lab, University of California, Davis, knows just where to find mosquitoes for his research.

Rice fields.

He's been collecting up to 3000 mosquitoes a night along the Yolo Causeway, located on Interstate 80 between Davis and West Sacramento. The Yolo basin is home to the Vic Fazio Yolo Wildlife Area.

It's easy to catch mosquitoes.

Syed is using carbon-dioxide traps to capture host-seeking mosquitoes. The female skeeters are seeking a blood meal (you, if you're around there). His traps entice them to "come on in."

"Once mosquitoes are lured to the vicinity," Syed says, "a suction fan traps them and sends them to the sleeve, a mesh bag that holds mosquitoes."

The mesh bag below holds 2000 mosquitoes. They are mostly Culex tarsalis, but also some Culex pipiens.

Culex mosquitoes are known for transmitting West Nile virus.

Syed and Leal are known for uncovering the mode of action for DEET, the chemical insect repellent used by more than 200 million people worldwide. Their groundbreaking research last year found that DEET doesn't jam a mosquito's senses or mask the smell of the host, as scientists previously thought for some 50 years. Mosquitoes avoid DEET because it smells bad to them.

ZAIN SYED, chemical ecologist at UC Davis, holds a bag of 2000 Culex mosquitoes he trapped between Davis and West Sacramento. He is using them for his research. (Photo by Kathy Keatley Garvey)

Close-Up

CLOSE-UP photo of a mesh bag of 2000 Culex mosquitoes shows them drawn to his hand below. He trapped the 2000 all in one night at the Yolo Causeway and has trapped as many as 3000 there in a single night. (Photo by Kathy Keatley Garvey)